3D printed Ergo kb parts: SLA vs. FDM?
3D printed Ergo kb parts: SLA vs. FDM?
Hi All,
I'm planning to print a plate & case for a handwired 46-key split kb. I have access to both SLA & FDM printers at a fab lab, so wondering which printer tech would be best to print various parts such as keycaps, plate, case etc. Function's more important than looks for me.
I'm allowed to use PLA or TPU for the FDM, and the default resin (ABS-like?) for SLA.
I'm thinking:
- Keycaps: SLA (I want really thin keycaps)
- Plate: ?? (not sure what's better for a thin & durable plate that allows a bit of flex when typing)
- Case: FDM (Due to costs, and easy to embed screws & magnets)
- Wrist rest (if any): FDM? Would TPU wrist rest be clean or comfortable?
- Gaskets, extra layers (if any): FDM (cuz TPU)
What do you think?
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You’ll want to coat the SLA parts in paint or some other coating that will block UV as they will turn yellowish and more brittle over time from UV. Also, a lot of the TPUs are pretty hard ~90 shore A, so check the hardness value compared to what you’d prefer.
Thanks for the input. I'll definitely spray paint the SLA parts. Not sure if spray painted keycaps will feel more "slippery" but I'll test first with some of them.
Good point with the TPU. I'm not sure what's available, but probably Ninjaflex (so 85A?)
You could SLA print a key cap to make a silicone mold then use something like Epoxy to make the final key cap.
Good point! I've been considering to print a TPU "sock" of some kind to put on top of a FDM/SLA printed keycap to mimic a silicone (or silicone-like) keycaps, just to see what it feels like. Maybe it's better to make a mold to try other materials too!
Definitely! Make a clean print. You can sand it, fill holes, and sculpt it perfectly before putting your shape in the silicone mold.
I've been printing sculpted palm rest prototypes in ninjaflex, because i had some on hand, but if i were you I'd buy ninjatek's Chinchilla. 75A and tested for skin compatibility.
i think its a reasonable idea, the TPU seals in air so its like a pool inflatable. TPU likes lower layer heights and you can get away with 5% infill but any less and the top surface will have holes in it and loose that pillowy feel. might need to go higher for a smoother surface. I recommend a non-crossing infill (otherwise you get blobs on the nozzle that will ruin your surface feel) and one that alternates directions, rather than stacking lines, so that the infill has more give. i tried gyroid at first, but 3D honeycomb was noticably softer because it alternates.
also, avoid sharp edges and corners in your design and slope the sides, don't have them vertical. this will also increase the softness
Oooh very interesting insights. I'll try to print a palm rest with your advice!
I've been printing sculpted palm rest prototypes in ninjaflex, because i had some on hand, but if i were you I'd buy ninjatek's Chinchilla. 75A and tested for skin compatibility.
i think its a reasonable idea, the TPU seals in air so its like a pool inflatable. TPU likes lower layer heights and you can get away with 5% infill but any less and the top surface will have holes in it and lose that pillowy feel. might need to go higher for a smoother surface. I recommend a non-crossing infill (otherwise you get blobs on the nozzle that will ruin your surface feel) and one that alternates directions, rather than stacking lines, so that the infill has more give. i tried gyroid at first, but 3D honeycomb was noticably softer because it alternates.